This article is part of the Guardian's World Cup 2014 Experts' Network, a cooperation between 32 of the best media organisations from the countries who have qualified for the finals in Brazil. theguardian.com is running previews from four countries each day in the run-up to the tournament kicking off on 12 June.

It is odd that something like this should have happened to someone like him of all people. "It was a momentary loss of control, or me being too emotional going into the tackle," says Sami Khedira, whenever he thinks back to the evening of 15 November 2013. The international that night against Italy was of the more physical kind, characterised by lots of little niggles, which momentarily caused the usually very composed German midfielder to get properly stuck in as well. His studs caught in the turf, he twisted his right knee and tore both his cruciate and the medial collateral ligaments.

There is not a great deal worse that can happen to a footballer's leg, which is why the diagnosis in such a case would under normal circumstances have been: Khedira's season is over. However, these weren't normal circumstances. They never are in years with a World Cup coming up in the summer. And especially not if you're 27 years old, when footballers are said to be at their best, and also in the form of your life. There are not all that many opportunities in a footballer's career to go to a World Cup and nobody to whom this competition means anything can afford to forego one lightly.

And thus within minutes of that momentous incident, Khedira was immediately back to his normal self. Controlled. Planning ahead. Almost ice-cold. Even before reaching hospital, he made a call from the ambulance to a doctor who had operated on his knee when he was a youth team player and agreed an appointment for an operation the very next day. He also telephoned the management team at his employers, Real Madrid, and asked them to send the club doctors to Germany the next morning.

When he returned from the hospital to the team hotel later that night in a wheelchair, he passed through a small party marking the head coach Joachim Löw's 150th international. Around noon the next day, less than 16 hours after getting injured, he was operated on in Germany.

From that day on, Khedira has subordinated his entire life to the goal of getting to the World Cup. His most dogged supporter in the process has been the national coach himself. "With his personality and experience he's indispensable to the team," said Löw, who stressed that he'd wait as long as possible for Khedira to recover and declared that he'd call up a player like Khedira even if he lacked match practice. And yet otherwise Löw had always emphasised that he'd consider only fit players for the tournament. While Mario Gomez was fairly unceremoniously left out following his injury ("Given the conditions in Brazil it was my view that he would not be able to cope physically"), you nevertheless got the impression that Löw would have taken Khedira to the World Cup on one leg if necessary.

Why is that so? Well, although his value is often not fully appreciated by the public at large, Khedira is in many ways Löw's key player. In a team characterised by outstanding attacking prowess he holds the defensive midfield together and is very much a player out of the "coach's favourite" mould: a good reader of the game, disciplined and perfect at implementing his respective manager's instructions. No wonder, then, that his coaches at Real Madrid, José Mourinho and Carlo Ancelotti, also value Khedira's style of play. In the midst of a host of artists he plays the unpretentious conductor and with the German national side not having a Pirlo or a Xavi, it needs at least a Khedira.

The son of a German mother and a Tunisian father, Khedira is a model professional. Having grown up in a hard-working, somewhat unsophisticated, provincial region of south-west Germany, his character was shaped as a boarder at VfB Stuttgart's youth academy, which has a code of conduct requiring the young players to say a proper "Good morning" to any member of staff they encounter. With Khedira as captain Stuttgart's juniors became German champions in successive age groups. Aged 19 he played his first game in the Bundesliga and by the time he was 20 he was already a champion again, this time with the first team. When Michael Ballack got injured just ahead of the 2010 World Cup, Khedira took his place and had an outstanding tournament, playing alongside the more attack-minded Bastian Schweinsteiger.

He subsequently moved to Real Madrid and ever since then a German national team-sheet without his name on it has been unimaginable – a picture-book career, in fact … until that November night last year.

Khedira approached his recovery as he had his entire career: with painstaking dedication and the utmost discipline. He took himself off for weeks to an isolated clinic in the Bavarian forest, far away from any form of distraction. "Taking my mind off what I needed to do would probably have made things worse," he said. "Lots of friends wanted to come and visit me, but even that I didn't allow."

Instead there was just work, work, work. While the national coach waited with trepidation and the German public viewed his chances of recovery with scepticism, Khedira fought his lonely battle. "During a time like that you get to know yourself better," he says. "You identify strengths in yourself, such as mental toughness and the ability to fight your way through. But your weaknesses become clearer to you, too." What weaknesses, it might well be asked.

On 11 May, Khedira made his comeback with Real Madrid, less than six months after getting injured in Milan, which for an injury like that is at the extreme bottom end of what is to be expected. That, of course, is no guarantee that he will be in top form by the time of the World Cup or that he will be able to cope with the rigours of up to seven games at such a tournament. However, as mentioned, Jogi Löw would probably have taken him on one leg. Now, at least, it's already one and a half.

Jens Kirschneck is the managing editor of the German football magazine 11 Freunde